RU2597573C2 - Stencil master for solar cell and method for printing electrode of solar cell - Google Patents

Abstract

FIELD: printing.

SUBSTANCE: invention relates to stencil master for use in printing conductive paste for simultaneous generation of bus electrode and a plurality of finger electrodes on solar element. Said stencil master includes an opening for bus electrode and multiple openings for finger electrodes, and the hole widths for finger electrodes is less than 80 mcm, and the stencil master has multiple blocked zones in the hole for bus electrode, formed only in positions aligned with holes for finger electrodes.

EFFECT: use of this stencil master for stencil screen printing method allows to cut the cost of solar cells, to protect connection between the bus electrode and a finger electrode against damage causing no increase of loss because of solar cells shadowing or loss of its aesthetic quality, and to make high-reliable solar cells of high capacity.

7 cl, 13 dwg, 1 tbl

Description

FIELD OF TECHNOLOGY

The present invention relates to a screen printing form, which allows the manufacture of solar cells with long-term reliability with good performance. In particular, it relates to a screen printing form in which the mask pattern of the busbar electrode is modified so that the electrodes can be formed at a low cost while maintaining high conversion efficiency; and a method for printing electrodes of solar cells using the specified screen printing form.

BACKGROUND

A solar cell manufactured using prior art technology is described with reference to its cross section (Fig. 1), the configuration of the front surface (Fig. 2) and the configuration of the rear surface (Fig. 3). In general, a solar cell includes a p-type semiconductor substrate 100 of silicon or the like, in which an n-type dopant diffuses to form an n-type diffusion layer 101, defining a pn junction. An antireflection film 102, such as a SiNx film, is formed on the diffusion layer 101. On the back surface of the p-type semiconductor substrate 100, an aluminum paste is applied substantially over the entire surface and is fired to form a back surface field layer (BSF) 103 and an aluminum electrode 104. Also on the back surface, a wide electrode 106, known as a bus electrode, is formed for down conductor by applying a conductive paste containing silver or the like, and burning. On the light receiving side, the finger electrodes 107 for collector and wide electrodes 105, known as bus electrodes, for collector from the finger electrodes, are arranged in a comb pattern so as to intersect at substantially right angles.

In the manufacture of solar cells of this type, the electrodes can be formed in various ways, including evaporation, electrodeposition, printing, and the like. The front finger electrodes 107 are typically formed using the printing / burning method described below due to ease of formation and low cost. More specifically, a conductive paste obtained by mixing silver powder, glass solder, an organic mediator and an organic solvent as main components are usually used as a front electrode material. The conductive paste is applied using a screen printing method or the like, and burned at a high temperature in a burning furnace to form a front electrode.

The screen printing method is described below.

The screen printing method uses a screen printing form, which is prepared by providing a mesh fabric 110 of orthogonally woven warp and weft yarns, covering the fabric with a photosensitive emulsion 111, exposing and removing portions of the emulsion to define a substantially rectangular opening of the screen (Fig. 4) . Screen printing form is placed above the place of printing. The printing paste (ink) is placed on a screen printing form and distributed on the screen. A flexible blade known as the squeegee 112 passes at a suitable squeegee stiffness (60 to 80 degrees), squeegee angle (60 to 80 degrees), pressure or applied pressure (0.2 to 0.5 MPa) and printing speed (from 20 to 100 mm / s) for transferring the printing paste to the printing location through the opening of the stencil. The printing paste applied to the printing location is then dried to form a printed pattern.

Immediately after the printing paste falls through the cells of the stencil, where there are no threads, and sticks to the place of printing, the printing paste does not adhere to the areas corresponding to the warp and weft threads in the stencil. Later, the printing paste adhering to the areas corresponding to the cells begins to spread, leading to a continuous printing pattern of uniform thickness.

As described above, the screen printing method is such that the printing paste filling the screen opening on the screen printing form is transferred to the printing site by the transferring movement of the printing squeegee (or blade), as a result of which the same pattern is formed at the printing site as the screen opening on the screen printed form.

The contact resistance between the front finger electrode 107 formed by the above method and the silicon substrate 100 and the resistance of the electrode connection strongly affect the conversion efficiency of the solar cell. To obtain a high efficiency (low series resistance of the element, high duty cycle (FF)), the contact resistance and the connection resistance of the front finger electrode 107 must have very low values.

Also, the electrode area must be small so that the light-receiving surface can receive as much light as possible. In order to improve the short circuit current (Jsc) while maintaining FF, the finger electrode must be formed so that it can have a reduced width (thin) and an increased cross-sectional area, i.e. a high dimensional ratio.

Although various methods are used to form the electrodes of solar cells, known methods for forming ultra-thin lines having a high dimensional ratio include a method of forming cutouts in an element and filling said cutouts with paste (JP-A 2006-54374) and an inkjet printing method . However, the first method is undesirable, since the step of forming cutouts in the substrate can cause damage to the substrate. Since the latter method, the inkjet printing method is developed by applying pressure to a liquid to inject droplets through a thin nozzle, it is suitable for forming thin lines, but it is difficult to obtain a height.

On the other hand, the screen printing method is an inexpensive high-performance method, since the formation of the printed pattern is easy, damage to the substrate is minimized by adjusting the applied pressure and the working speed per element is high. If a conductive paste having high thixotropy is used, an electrode can be formed that retains its shape after transfer and has a high dimensional ratio.

As discussed above, the screen printing method is more suitable for forming electrodes with a high size ratio at a low cost than other printing methods.

However, when thin lines are printed using the above method, there is a problem that the connection between the bus electrode and the finger electrode becomes very thin and breaks during operation. If the finger electrode on the light receiving side locally thins out or even collapses, this area becomes the controlling resistance factor, leading to a drop in the duty cycle.

The cause of the destruction is the difference in film thickness when connecting the bus electrode and the finger electrode. In screen printing, the growth of the paste is proportional to the size of the hole. Namely, a large increase in paste occurs for a bus electrode corresponding to a large hole, while a small increase in paste occurs for a finger electrode corresponding to a small hole. Thus, a difference in film thickness arises between the tire electrode and the finger electrode. If the electrodes are burned in this state, destruction occurs at the boundary between the bus electrode and the finger electrode, since the bus electrode with a large increase gives a large shrinkage. If the difference is small, the phenomenon arises that the connection between the bus electrode and the finger electrode becomes very thin.

In addition, in the screen printing method, the printing direction (the direction of movement of the printing squeegee) also becomes a contributing factor to the destruction. To prevent the destruction of the finger electrode, the screen printing form 1 is usually given such a pattern that the print direction and the hole 2 of the finger electrode are essentially parallel, and the print direction and the hole 3 of the bus electrode are essentially perpendicular (Fig. 8). With this design, the printed electrodes are formed so that the width of the connection between the bus electrode 13 and the finger electrode 12, located on the side upstream of the finger electrode 12, is very narrow (Fig. 9). This narrowing occurs especially when thin lines are printed. This is because at the junction between the hole 2 of the finger electrode and the hole 3 of the bus electrode, the print squeegee falls into the hole 3 of the bus electrode, causing less buildup of the paste in this connection. On the contrary, the width of the connection between the bus electrode 13 and the finger electrode 12, located on the lower side in the printing direction, tends to be broadened due to the greater growth of the paste (Fig. 9). It is noticeable that the printing plate includes blocked or masked zones 5.

In addition, a saddle formation phenomenon is likely to occur, since the hole 3 of the busbar electrode is significantly wider than the hole 2 of the finger electrode, and the squeegee 112 moves across the printing plate perpendicular to the hole 3 of the busbar electrode, as described above. The phenomenon of saddle formation is that when a wide open area such as a tire is printed, the squeegee 112 presses against said open area (FIG. 5) and the central portion 113 is pressed deeper than the edges of the paste in the width direction of the busbar electrode (FIG. 6). The occurrence of a saddle formation phenomenon causes a difference between the height of the busbar electrode at its edge in the direction of its width and the height of the finger electrode. Since the edge of the bus electrode with a large increase has a higher shrinkage factor during burning of the electrode, the connection between the bus electrode 13 and the finger electrode 12 can be destroyed 114 (Fig. 10). Note that in FIG. 10 dashed line means the connection between the bus electrode 13 and the finger electrode 12.

Even when the finger electrode and the bus electrode are printed separately, a saddle formation phenomenon occurs at the bus electrode, preventing the destruction of the junction of the bus electrode and the finger electrode at the same time.

To solve the above problem, JP-A 2009-2724 05 discloses broadening of the connection between the bus electrode and the finger electrode. When using this method, however, spots and lumps are formed, since the connection between the bus electrode and the finger electrode is very thick. This increases problems such as shading loss and degradation. Since the solar cell is actually a device that is used in sunlight, there is a lot of chance of public observation, unlike other semiconductor devices. Accordingly, not only performance, but also appearance is very important for the solar cell. The method of the above patent has the problem that since the connection between the bus electrode and the finger electrode is thick, the finger electrode becomes intermittent in thickness, losing in aesthetics.

It is also known how to prevent the squeegee from falling into the tire hole when performing screen printing by selecting the position of the screen printing plate rotated by a different angle than a multiple of 90 ° relative to the direction of movement of the squeegee (Fig. 7). This method, however, has a problem in that, since the direction of movement of the squeegee is not parallel to the finger hole, the finger electrode is smeared, losing print accuracy.

SUMMARY OF THE INVENTION

Technical problem

Although this invention was made to overcome the above problems, its purpose is to provide a screen printing form for use with solar cells and a method of printing electrodes of solar cells through this screen printing form, whereby electrodes having a high size ratio and low resistance are formed, making possible low-cost manufacturing of solar cells with high conversion efficiency.

Solution

The present invention addresses the above problems and relates to a method for manufacturing a solar cell by printing a conductive paste while forming a bus electrode and a finger electrode. Regarding the formation of the electrode by screen printing through a screen printing form including a hole for the bus electrode, it was found that if the hole for the bus electrode is partially provided with a blocked zone, the pressure applied by the squeegee to the paste filling the hole is reduced. In this case, the destruction of the electrode is restrained. The present invention is based on this discovery.

Accordingly, this invention provides a screen printing form for use with solar cells and a method for printing electrodes of solar cells specified below.

[1] Screen printing form for use in printing a conductive paste with the simultaneous formation of a bus electrode and a finger electrode on a solar cell, characterized in that the screen printing form includes a hole for a finger electrode having an opening width of less than 80 μm, and an opening for a bus electrode, including a blocked zone.

[2] Screen printing form according to paragraph [1], wherein said blocked zone corresponds to 60% of the tire area, calculated from the contour of the hole for the tire electrode of the screen printing form.

[3] A screen printing form according to [1] or [2], wherein said blocked zone in the hole for the bus electrode is at a distance of 50 to 700 μm from the boundary between the hole for the finger electrode and the hole for the bus electrode.

[4] A method of printing electrodes of solar cells, characterized in that the conductive paste is printed using a screen printing form according to any one of [1] to [3] and moving the squeegee in a direction perpendicular to the longitudinal direction of the tire electrode.

It should be noted that destruction rarely occurs with a commonly used hole for a finger electrode having a width of 80 to 100 μm. This invention is effective for thin lines corresponding to a hole width for a finger electrode of less than 80 μm.

In order to obtain the full advantage of the present invention, when the electrodes of the solar cell are printed using a screen printing form having the above-described features, it is desirable that the printing direction is substantially perpendicular to the longitudinal direction of the bus electrode.

Advantageous Effects of the Invention

The use of the proposed screen printing form allows to reduce the cost of manufacturing solar cells, to prevent the connection between the bus electrode and the finger electrode from destruction without increasing losses from shading or compromise with the aesthetic appearance of solar cells, and to produce reliable solar cells with high performance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of electrodes of a typical solar cell.

FIG. 2 is a plan view showing a configuration of a front surface of a typical solar cell.

FIG. 3 is a plan view showing a configuration of a rear surface of a typical solar cell.

FIG. 4 schematically depicts a printing step using a conventional screen printing form.

FIG. 5 schematically depicts the phenomenon of saddle formation during a printing step using a conventional screen printing form.

FIG. 6 is a cross-sectional view showing an electrode profile after printing using a conventional screen printing form.

FIG. 7 schematically depicts one typical method for avoiding collapse using a conventional screen printing form.

FIG. 8 is an enlarged view of openings in a conventional screen printing form.

FIG. 9 is an enlarged view of electrodes printed using a conventional screen printing form.

FIG. 10 is a cross-sectional view of the connections between the bus electrode and the finger electrode, taken along line AA in FIG. 9.

FIG. 11 is an enlarged view showing openings in a screen printing form in one embodiment of the present invention.

FIG. 12 is an enlarged view of electrodes printed using a screen printing form in one embodiment of the present invention.

FIG. 13 is a cross-sectional view of the connections between the bus electrode and the finger electrode, taken along line BB in FIG. 12.

DESCRIPTION OF EMBODIMENTS

One embodiment of the present invention is described in detail below. The screen printing form for use in the manufacture of solar cells includes a portion providing a bus electrode including a blocked area. In a preferred embodiment, the blocked area is up to 60%, more preferably up to 55% of the area of the hole calculated by the contour of the bus electrode. The present invention causes this effect to a greater extent when the blocked area is at least 30%, more preferably at least 45% of the opening area. The screen printing form also includes a hole for the finger electrode having a width of less than 80 microns, preferably from 40 microns to less than 80 microns, more preferably from 40 to 7 5 microns, even more preferably from 45 to 70 microns and most preferably from 50 to 60 microns.

FIG. 11 depicts a typical screen printing form of the present invention. In FIG. 11, the screen printing form 1 includes a plurality of finger electrode holes 2 extending parallel to the print direction (indicated by an arrow), and a large width bus hole (Wb) 3 extending perpendicular to the print direction. The width Wb is preferably from 0.5 to 3 mm, more preferably from 1 to 2 mm. In the screen printing form 1 according to the present invention, the hole for the bus electrode 3 includes a plurality of blocked zones 4 located therein. These blocked zones 4 are formed in positions aligned with the longitudinal direction of the openings 2 for the finger electrodes. The blocked zones 4 inside the holes 3 for the bus electrode are preferably located at a distance (Wc) of 50 to 700 μm, more preferably 100 to 300 μm from the boundary between the hole 2 for the finger electrode and the hole 3 for the bus electrode. If this distance is less than 50 μm, the amount of paste removed can be reduced, contributing to the destruction. If the distance exceeds 7 00 μm, the ejection of the paste by the squeegee pressure becomes sufficient for the occurrence of the saddle formation phenomenon, leaving the danger of destruction due to different shrinkage during burning. The distance between the blocked zones 4 is preferably from 100 to 2000 μm, more preferably from 300 to 1000 μm.

The total area of the blocked zones 4 is up to 60% of the total area of the hole 3 for the busbar electrode and the blocked zones 4 (that is, the area of the bus calculated from the contour of the hole 3 for the busbar screen-printed electrode). The width Wf of the finger electrode hole 2 is less than 80 μm.

The use of a screen printing form, organized as described above, is effective in preventing the destruction of the finger electrodes, the squeegee falling into the hole for the bus electrode during printing, and thickening of the finger electrode when switching from the tire electrode to the finger electrode, as best shown in FIG. 12 and 13.

One typical method for manufacturing a solar cell using the screen printing form of the present invention is now described. The present invention is not limited to a solar cell made using this method.

The cut off p-type single-crystal {100} silicon substrate, in which high-purity silicon is doped with an element of group III, such as boron or gallium, to give it a specific resistance of 0.1 to 5 Ohm · cm, is etched with a concentrated alkaline solution of sodium hydroxide or hydroxide potassium, having a concentration of from 5 to 60% of the mass, or a mixed acid of hydrofluoric acid and nitric acid to remove damaged during operation, the surface layer.

A single crystal silicon substrate can be prepared using the CZ or FZ method.

The surface of the substrate is then provided with microscopic protrusions known as texture. Texture is an effective way to reduce the reflectivity of solar cells. The texture can be easily provided by immersing the substrate in a hot alkaline solution of sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate or sodium hydrogen carbonate (concentration from 1 to 10% by weight) at a temperature of from 60 to 100 ° C for from about 10 to about 30 minutes. Often, the proper amount of 2-propanol is dissolved in said alkaline solution to facilitate the reaction.

Texturing is followed by washing with an aqueous acid solution such as hydrochloric acid, sulfuric acid, nitric acid or hydrofluoric acid, or a mixture thereof. Washing with hydrochloric acid is preferred in terms of cost and effectiveness. To improve purity, washing can be performed by mixing from 0.5 to 5% by weight of aqueous hydrogen peroxide with aqueous hydrochloric acid and heating to from 60 to 90 ° C.

An emitter layer is formed on the substrate by diffusion from the gas phase using phosphorus oxychloride. In ordinary silicon solar cells, the pn junction must be formed only on a light-receiving surface. For this, it is necessary to use a suitable means to avoid any pn junction on the back surface, for example, by diffusing when two substrates are paired together, or by forming a SiO ₂ or SiN _x film on the back surface as a mask for diffusion up to diffusion. At the end of diffusion, the glass formed on the surface is removed using hydrofluoric acid or the like.

Then, an antireflection film is formed on the light receiving surface. Using a plasma chemical vapor deposition (CVD) system to form a film, a SiNx film is deposited to a thickness of about 100 nm. A mixture of monosilane (SiH ₃ ) and ammonia (NH3) is often used as a reacting gas, although nitrogen can be used instead of NH ₃ . Also, hydrogen can be mixed with the reacting gas to adjust the process pressure, dilute the reaction gas, or enhance the volume passivation effect when the substrate used is polycrystalline silicon.

The back electrode is then formed using the screen printing method. On the back surface of the substrate, a paste obtained by mixing silver powder and glass solder with an organic binder is screen printed onto a tire screen, after which a paste obtained by mixing aluminum powder with an organic binder is screen printed onto an area excluding the tire. After printing, the pastes are burned at a temperature of from 700 to 800 ° C for 5 to 30 minutes, forming the back electrode. The back electrode is preferably formed by screen printing, although it can be formed by evaporation, sputtering or the like.

Then, the front electrode is formed by a screen printing method using a screen printing form according to the present invention.

More specifically, a paste obtained by mixing silver powder and glass solder with an organic binder is screen printed on the front surface of the substrate using a screen printing form having a comb printing screen designed for a finger electrode width of 30 to 80 μm and a distance between finger electrodes of 0.5 to 4.0 mm.

The screen printing form of the present invention can be obtained simply by providing a hole for the bus electrode with blocked zones, as shown in FIG. 11, without the need to change the conventional stencil of the solar cell mentioned above.

Typically used screen printing forms include holes for finger electrodes having a width of from 80 to 100 μm. In this case, the aforementioned destruction rarely occurs, since the finger electrodes are quite wide and can be printed thick. However, when the lines are narrowed to a width of the hole for the finger electrode of less than 80 μm, the difference in film thickness between the bus electrode and the finger electrode becomes larger. Then destruction can occur due to various thermal shrinkage (Fig. 9).

On the contrary, when a solar cell is manufactured by printing a bus electrode and a finger electrode at the same time, the risks of destruction can be avoided by using a printing step using a screen printing form including an opening for the bus electrode including blocked areas comprising up to 60% of the opening area calculated along the contour of the bus electrode (Fig. 13).

In order to obtain the full advantage of the present invention, when the solar cells are manufactured by printing electrodes through a screen printing form having the above-described features, it is desirable when the printing direction is substantially perpendicular to the bus electrode.

The use of the screen printing plate according to this invention has the additional effect of preventing the finger electrode from thickening, since the presence of blocked zones in the hole for the bus electrode reduces the amount of paste extruded on the last side of the print.

When the blocked area is partially included in the hole for the bus electrode, an unprinted area may remain after printing. However, this does not cause problems with the appearance, since the copper terminal is coated with solder and attaches to the specified area during the manufacture of the module. As long as the area of the busbar electrode is at least 40% of the standard area of the busbar electrode, the bond strength of the output to the busbar electrode is maintained. As the amount of busbar electrode used is reduced, solar cells can be manufactured at lower cost. The inclusion of blocked zones in the hole for the bus electrode on the screen printing plate eliminates any damage to the connection between the bus electrode and the finger electrode.

Once the electrodes are formed using the above method, they are burned by heating in air at a temperature of from 700 to 800 ° C for 5 to 30 minutes. Burning of the rear electrode and the electrode of the light receiving side can be performed simultaneously.

EXAMPLES

Examples and comparative examples are given below by way of illustration and not by way of limitation.

[Examples and comparative examples]

To demonstrate the advantages of this invention, solar cells were manufactured by treating thirty (30) semiconductor substrates as follows.

Provided screen printing forms carrying a conventional stencil A having a hole width for a finger electrode (Wf) of 60 μm (comparative example, FIG. 8), a screen B including a hole for a bus electrode including blocked zones (FIG. 11 ), in other respects equivalent to stencil A, and stencil C having a hole width for a finger electrode (Wf) of 100 μm (comparative example, FIG. 8) as a stencil for printing. All stencils typically had a hole width for the bus electrode (Wb) of 1.5 mm.

More specifically, on the stencil B, the hole for the bus electrode was located at a distance of 100 μm from the boundary between the hole for the finger electrode and the hole for the bus electrode, the distance between the blocked zones was 1000 μm, and the total area of the blocked zones was 55% of the bus area calculated along the contour of the hole for the bus electrode.

A cut-off, p-type 100 silicon substrate in the form of a square of 15 cm, having a thickness of 250 μm and a resistivity of 2.0 Ω · cm, was provided cut off by boron {100}. The substrate was immersed in a concentrated aqueous solution of potassium hydroxide to remove the layer damaged by treatment, textured, heated to 850 ° C in an atmosphere of phosphorus oxychloride to form emitter layer 101, and etched with hydrofluoric acid to remove phosphoric glass, followed by washing and drying. Then, a SiNx 102 film was formed using a plasma CVD system. On the back surface, a paste of silver powder, glass solder and an organic binder was printed by screen printing in tire figure 106, and then a paste of aluminum powder and organic binder was printed by screen printing in figure 104, excluding the tire. The organic solvent was evaporated to give a semiconductor substrate having a back electrode formed thereon.

Then, a conductive paste based on silver powder, glass solder, an organic carrier, and an organic solvent and additionally containing metal oxide as an additive was applied to an antireflection film of a semiconductor substrate using a screen printing form having a selected printing screen, with a doctor blade hardness of 70 degrees, an angle squeegee 70 degrees, an applied pressure of 0.3 MPa and a printing speed of 50 mm / sec. After printing, the substrate was heated in a clean oven at 150 ° C for drying and burned in air at 800 ° C.

Thirty (30) solar cells manufactured in this way were observed for electrodes under an optical microscope and evaluated using a solar simulator (atmosphere 25 ° C, irradiation intensity 1 kW / m ² , AM spectrum 1.5 Global). The width of the finger electrodes after printing and the width of the joint were also observed under an optical microscope, inspecting any damage. The average results of the example and comparative examples are shown in table 1.

Failure of the connection between the bus electrode and the finger electrode was observed at standard level A, but was not observed in the method of the present invention, as well as at level C using a large hole width.

Short circuit current dropped at level C using a large finger electrode width. This drop is caused by shading losses due to the increased width. The fill factor at level B, free from destruction, was 75.1%, which was approximately 1.5% higher than at level A undergoing destruction.

In the prior art, the connection between the bus electrode and the finger electrode has been destroyed. When using the screen printing form of the present invention, electrodes having a high dimensional ratio can be formed without danger of destruction, without increasing the number of steps.

As shown above, this invention ensures that the bus electrode and the finger electrode are formed without the risk of destruction in the connection between the bus electrode and the finger electrode. Thus, solar cells having high conversion efficiency can be manufactured with high yields.

List of numbers

1 screen printing form

2 hole for finger electrode

3 hole for bus electrode

4 blocked zone in the hole for the bus electrode

5 blocked zone

12 finger electrode

13 front busbar electrode

100 p-type semiconductor substrate

101 n-type diffusion layer

102 antireflection film (SiNx film)

103 BSF layer

104 aluminum electrode

105 front busbar electrode

106 rear busbar electrode

107 finger electrode

110 mesh

111 emulsion

112 squeegee

113 dent

114 destruction

Claims (7)

1. Screen printing form for use in printing a conductive paste for simultaneously forming a bus electrode and a plurality of finger electrodes on a solar cell, said screen printing form including a hole for a bus electrode and a plurality of holes for a finger electrode, the holes for the finger electrode having a width the holes are less than 80 μm and the screen printing form has many blocked zones in the hole for the bus electrode, formed only in polo lined with holes for the finger electrodes. 2. Screen printing form according to claim 1, in which the total area of the blocked zones is from 30% to 60% of the area of the hole for the bus electrode, calculated on the contour of the hole for the bus electrode of the screen printing form. 3. Screen printing form according to claim 1, in which the specified blocked zone in the hole for the bus electrode is at a distance of from 50 to 700 μm from the boundary between the holes for the finger electrode and the hole for the bus electrode. 4. Screen printing form according to claim 1, in which the blocked areas are aligned with the longitudinal direction of the holes for the finger electrode. 5. Screen printing form according to claim 1, in which the distance between the blocked zones is preferably from 100 to 2000 microns. 6. Screen printing form according to claim 1, in which the width of the hole for the busbar electrode is from 0.5 to 3 mm. 7. A method of printing electrodes of a solar cell, in which a conductive paste is printed to simultaneously form a bus electrode and a plurality of finger electrodes on the solar cell, by using the screen printing form according to any one of claims. 1-6 and the movement of the squeegee in a direction perpendicular to the longitudinal direction of the tire electrode.

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